I used Sennheiser PX100 as headphones and two different mp3s which are both ripped at the best quality i know of, in VBR. The mp3 songs have a average bitrate of 178 kbps and 238 kbps.

The conclusion here was that the e270 has a richer sound both in regards to high and low (any)frequency, and the sounds are more dynamic because of this. Zen V Plus seams to have a poorer frequency range and less signal/noise ratio than the e270. The Loudness button(Bass Boost) really boosts the level of distortion, and kills the sounds completely with the PX100 headphones. This has probably to do with the low S/N ratio of the player.

I havent tested with the original Zen V Plus earbuds or the e270's earbuds.